2. The cocoa beans are ground into powder, and the cocoa powder and softened cocoa butter are mixed in a bowl. Stir to make it a smooth paste. Remove caking with fork and food processor or immersion blender.
3. Pour the cocoa powder paste into hot water and stir, and continue to heat but not boil. Pour the hot mixture into the bowl.
4. Sift the sugar and powdered sugar into another bowl, try to remove small pieces, then pour the sugar mixture into the hot cocoa powder mixture and stir. Add milk. Stir until smooth.
5. Spread the mixture thinly on the bottom of various containers. If you want a rectangular chocolate bar, put it in a rectangular container. You can also use candy molds.
6. Put it in a freezer or refrigerator overnight to cure it.